To facilitate proper use of a personal care device, modem devices have sensors embedded therein to monitor use, timing, etc. For example, electric toothbrushes have been designed to provide a timer function such that a user knows to brush for a minimum recommended amount of time. The timer function can include an audible sound, haptic feedback, or other notification mechanism to let the user know when a predetermined amount of time has elapsed. This provides the user with an indication that they have brushed their teeth for an adequate amount of time. Electric razors have been designed with sensors that can identify areas of the face that have not been shaved during a shaving session to identify missed areas. Similarly, skin cleaning devices have been designed with sensors that can identify where they have been used and where areas have been missed.
For example, for oral hygiene, proper tooth brushing, including length and coverage of brushing, and regular flossing, help ensure long-term dental health. Many dental problems are experienced by individuals who either do not regularly brush their teeth or floss, or who do so inadequately, especially in a particular area or region of the oral cavity. Among individuals who do brush and floss regularly, improper cleaning habits can result in poor coverage and thus surfaces that are not adequately cleaned during a cleaning session, even when a standard brushing or flossing regimen is followed. Another mechanism to facilitate proper brushing technique is to ensure that there is adequate cleaning of all dental surfaces, including areas of the mouth that are hard to reach or that tend to be improperly cleaned during an average brushing session. One way to ensure adequate coverage is to determine or track the position of the toothbrush in the mouth during a brushing session and compare that to a map of the dental surfaces. For example, a system with sensors positioned in fixed relationship to the teeth of the user could track the movement of a toothbrush over the user's teeth. Alternatively, the toothbrush could include one or more internal sensors that attempt to track movement of the device within the mouth. However, these localization and tracking systems are either expensive or are unable to adequately localize or track the position of the personal care device.
Accordingly, there is a continued need for personal care devices that adequately localize the device within the use area to ensure proper and complete use.